Top of La Liga by four points from arch rivals Real Madrid, Barca also have a UEFA Champions League quarter-final with Paris Saint-Germain and the Copa del Rey final against Athletic Bilbao ahead of them in the coming months.
Luis Enrique's side return to league action against Celta Vigo this weekend, and Pique knows it is imperative they pick up where they left off prior to the international break - having beaten Real in El Clasico to cement their place at the summit.
"The most important time is now," Pique said. "We have a series of tough matches, including the Champions League quarter-final.
"We know it will be very hard and we're going to need to perform at our best if we want to win titles.
"We have improved as a team as the season has progressed and we're feeling very confident right now. We have learned from last season and have tried to improve things.
"Every month is decisive. We may not be able to win titles, but we can lose them. We have to go game by game, knowing that we can't afford to drop points in the league and that the Champions League quarter-finals are of vital importance to the club.
"If we don't win any trophies, all this hard work will have been for nothing."
